Awesome dude who lived in Italy a loong time ago. His best known book is "The Prince", which contains political tips for rulers. Some of his ideas from this book (and maybe a few from "The Discourses") as far as I can remember:

-The Prince must be ruthless.
-Effectiveness > good/bad.
-Power should be acquired, not hereditary.
-People are moral because others are watching. Political morality is lying and killing. Politicians must learn how NOT to be good.
-Be feared; cruelty is a part of the state. But remember that the best fortress that exists is to avoid being hated by the people. Three ways to avoid being hated: Don't be erratic. Don't be a coward, FIGHT. And don't do anything for no reason.
-Concept of seeming vs being: The Prince, while seeming human, must learn how to be a beast. Like a fox (cunning and tricky) or a lion (powerful).
-And my personal favorite, he talks about these two dudes named Agathocles the Sicilian and Oliverotto of Fermo who both held meetings/banquets with leaders and important people and killed them all and took over as ruler. Point is, the elite can be killed, they're not important. The people are important.
-Choose the people around you wisely. Ass kissers prevent you from seeing the truth cause they're always like "yes, you're awesome" to everything.
-For a strong society, you must assume that everyone has the potential to be evil and make laws accordingly. People act good only when forced, laws exist where desire is.

Lindsay Lohan was once photographed walking around with a copy of Machiavelli's book. True story.

whether you subscribe to the ideas of a 16th century Italian political philosopher. But experiments have shown that reactions to Machiavelli act as a kind of litmus test, delineating differences in temperament that can be confirmed with more traditional personality inventories. High Machs constitute a distinct type: charming, confident and glib, but also arrogant, calculating and cynical, prone to manipulate and exploit

True low Machs, however, can be kind of dependent, submissive and socially inept. So be sure to invite a high Mach or two to your next dinner party.